Study On Approaches Of Civil Aircraft Spares Support Based On Performance (PBL)

With the advance of science and technology and quick development of aircraft manufacture, theAdvanced Regional Jet (ARJ21) with autonomous intellectual property and international AirworthinessStandard has rolled off the assembly line and made its maiden flight successfully. With it comes theproblem of civil aircraft support on schedule. In the support system of civil aircraft spares, spares support isone of the key problems. Being based on modern PBL guarantee theory and aiming at ARJ21, this thesisconducts related research on spares support of civil aircraft, constructs PBL based appraisal model forsupport’s process and capability and entropy weight forecasting model for support accuracy, presents themethod and content of economic analysis for aircraft spares support. And finally this study takes ARJ21asan example and divides its spares support into initial and sustainable supports on the basis of PBL theory;and then it proposes relevant spares support models respectively, and carries out quantitative verificationfor models by related data.The PBL guarantee theory has been widely applied in support activities of military airplane for a longtime and has achieved high performance. But this guarantee is seldom utilized in the field of civil aircraft.This article at first shows graphic PBL support process and then describes the probabilistic sequenceoperation of support process; and it accordingly clarifies the relation between PBL based aircraft reliabilityand spares quantity. The aircraft reliability is closely linked with spares quantity which is also closelyconnected with product’s inherent failure rate, usage, inventory quantity, maintenance cycle, fleet size. Inthis article, let fleet size N=50，respectively suppose maintenance cycle tr=30days or60days，usage β=0.5or0.8， and availability A0=0.8or0.95，then the relation diagram of reliability and spares quantitycan be simulated by using software MATLAB.Next, it explores the support precision of aircraft spares support system by use of information entropyweight theory, distributes the weight of each error index, and calculates the variation coefficient of eachsingle forecasting method. Then it makes use of the weights of each error index and each single forecastingmethod to determine the coefficient matrix of combined weights. And lastly, this article demonstrates theprecision of this entropy weight forecasting model by case study.At last, the article makes economic analysis for PBL based aircraft spares support. Firstly, it isnecessary to obtain financial statement of aircraft spares support and audit it by financial analysis software.Then, based on the audit report, it synthesizes statement of cash flow, generates structure financialstatement and analyzes sensitivity analysis of profit and loss elements for support costs, sustainabledevelopment for support activity based on Van Home model, economic value added for support activity,free cash flow, and profit and loss based on K-S model and marginal model; and it uses Altman model toevaluate success and failure of support activity, Wole index to evaluate the support credit level andRappaport model to assess support value.In the PBL based support strategy of civil aircraft spares, this study, in view of ARJ21, raisesforecasting models for circulating parts, reparable parts, and expendable part in the initial spares support. Inthe sustainable spares supports and in term of the six failure models, for the not-reparable parts, this thesisbuilds up the demand calculation model by the update process in stochastic process. Since the failuredistribution function is complex and it is difficult to solve it with a conventional approach, this study adoptsMonte Carlo to simulate number of failures and compute the demand of not-reparable parts. For thereparable parts, according to the impact upon the spares life cycle by different maintenance methods, thisresearch introduces maintenance index to quantize maintenance degree, uses genetic algorithm to optimize the parameter estimation of maintenance degree and applies generalized update process to construct ademand model for reparable parts. In the end, a calculation example is utilized to check the effectiveness ofthe model.